1. Field of the Invention
The invention relates to a planetary transmission in the walking mechanism of a dragline.
2. Discussion of Prior Art
A walking dragline typically includes a main housing and a boom which extends upwardly and outwardly from the main housing and has thereon a sheave for supporting a hoist rope. The hoist rope extends from a bucket hoist mechanism and over the sheave to a bucket for causing vertical movement of the bucket. A drag rope extends between a bucket drag mechanism and the bucket for causing horizontal movement of the bucket. The main housing is supported by a tub that sits on the ground when the dragline is engaged in digging operations. A pair of walking mechanisms are mounted on the opposite sides of the main housing and are operable for moving the main housing over the ground between digging operations.
U.S. Pat. No. 5,600,905, which is assigned to the assignee hereof and which is incorporated herein by reference, discloses a planetary transmission for driving the walking mechanism of a dragline. The planetary transmission is coupled to a motor output mechanism such as a shaft. The planetary transmission reduces the speed of the shaft, causing an increase in torque. A planetary transmission ordinarily includes a sun gear, a ring gear, planet gears which mesh with both the sun gear and the ring gear, and a carrier which is connected to and moves with the planet gears. In the transmission of U.S. Pat. No. 5,600,905, the sun gear is driven through a parallel shaft gear set by the motor output shaft, and the output carrier is drivingly connected to the walking mechanism.